Centerboard.



110.834.840." PATBNTED 002|?.v so, 1906. y D. M. MGLEAN.

UBNTBRBOARD.

APPLICATION FILED Nov. 3. 1905.

2 SHEETS-SHEET 1.

cz, I f

WITN 55555: v

`PATENTED OCT. 30, 1906.

D. M.v MOLBAN. CENTERBOARD. APPLICATION FILED NOV. 3, 1905.

Nv' E NTDR; IZKL'MLM l UNITED sTATEsv PATENT oEEroE.

DONALD M. MCLEAN, OF BOSTON, MASSACHUSETTS.

` CENTERBOARD.

Specification of Letters Patent.

Patented oct.- 30, 1996.

Application filed November 3, 1905. Serial No. 285.742.

' and useful Improvements in Centerboards, of

which the following is a specification.

This invention has for its object to provide an improved centerboard forvessels, adapted to be raised and lowered by a flexible controller, suchas a rope or chain, without liability of displacement of the controllerlfrom its proper position relatively to the centerboard, and thereforewithout liability of the fouling of the controller between the sides ofthe centerboard and the sides of the trunk or casing in which it moves.

The invention also has for its object to provide improved means forsecuring the centerboardin various positions.

The invention consists in the improvements which I willnow proceed todescribe and claim.

Of the accompanying drawings, forming a part of this specification,Figure 1 represents a side elevation of a centerboard trunk or casing,showing in dotted lines a centerboard embodyin my invention. Fig. 2represents a longitudinal section ofthe casing, showing the centerboardpartially in section and partly in elevation, the centerboard beingraised. Fig. 3 represents a view similar to Fig. 2, showing thecenterboard lowered. Fig. 4 represents a viewsimilarto Fig. 2, showing adifferent form and arrangement of the controller. Fig. 5 represents asection on line 5 5 of Fig'. 4. Fig. 6 represents a side elevation of aortion of the centerboardtrunk, showing tIhe securing device illustratedin section in Fig. 5. Fig. 7 represents a section on line 7 7 of Fig. 6.Fig. 8 represents a view similar'to Fig. 6, showing a different forml ofcenterboard-securing means. Fig. 9 represents a section on line 9 9 ofFig. 8. Fig. 10 represents an end view of the removable set-screw handleshown in Fig. 9. Fig. 11 represents a sectional view of a modification.

The same reference characters indicate the same parts in all thefigures.

In the drawings, a represents a trunk or casing adapted to receive acenterboard l), the said trunkbeing suitably built into the hull of thevessel and open at its lower edge through the keel c of the vessel. Thecenterboard b is pivoted at d to the trunk, the pivot being located inclose proximity to the keel and to the lower edge of the ycenterboardwhen the latter is in its raised position. The pivot is also locatedconsiderably nearer'the front end of the centerboard than the rear endto permit a considerable projection f of the centerboard below the keel,as shown in Fig.

` 3, in which b represents the forward edge of the centerboard. The backedge of the centerboard is provided with a slot or channel b2, adaptedto receive a iiexible controller, whreby the centerboard is raised andlowere v The controller maybe a sprocket-chain e,

as shown in Figs. 1, 2, and 3, or it may be 'a rope e, as shown in Figs.4 and 5, or the controller may be of an other suitable construction. Oneendof t e controller is affixed to the centerboard at b3., the point ofconnection between the controller and the centerboard being at one endof the bottom of the slot bf. Means are provided for uiding thecontroller in the plane of the slot I. Said means may be aguiding-orificef, formed in the top of the trunk a above the rear ortionof the centerboard or a guiding-ori ce j", formed in the forward end ofthe trunk, or a ulleyfz, journaled in the forward portion o the trunkand located between the centerboard, and an orificef3 in the top of thetrunk. In either case the guiding device is arran ed to kee thecontroller in line with the sIot.` of sufficient depth to enable itssides to act as guards, preventingthe controller from slipping sidewisefrom the centerboard and becoming fouled between the centerboard andeither side of the trunk.

The bottom of the slot or channel is curved in the direction of thelength of the centerboard, so that when said centerboard is'lowcontrolling device resting in contact with the bottom of the wellthroughout the entire length of that portion which is below the surfaceof the water.

Owin to the fact that the bottom of the slot or c annel b2 is curved, asdescribed, the

rope or chain will closely t the said bottom along practically theentire len th' thereof that is below the water-line, whet er thecenterboard is partially or fully lowered. This construction isparticularly useful for the IOO purpose described when the said slotl orchannel 1s formed in the upper edge of the centerboard instead of in itsrear edge, and the centerboard is mounted, as shown, to swingapproximately ninety degrees. This is because in spite of theconsiderable range of movement there is no space between the rope orchain and the bottom of the channel at any point below the water-lineinto which seaweed could float and lodge, and said curve prevents anyslack occurring in the rope or chain, due to drag by the water throughwhich the vessel is sailing.

The centerboard is preferably so formed that when raised its forwardedge b will be elevated above the bottom of the keel, so that thecenterboard will be protected by the keel in case the latter runs upon arock or other obstruction. The forward edge 'of the centerboard ispreferably recessed at b5 to ermit the solid portion of the keel toextend ack nearly to the pivot d, thus reducing to the minimum thelength of the opening through the keel for the accommodation of thecenterboard and correspondingly increasing the strength of the hull atthis point.

When the controller is a sprocket-chain c, the bottom of the slot b2 isprovided with sprocket-teeth e, adapted to engage the links of saidchain, so that when the centerboard is lowered it is engaged with alarge number of links, as shown in Fig. 3, the strain exerted on thesecuring pin or device b3 being thus relieved and distributed along thelinks and teeth. The links may be numbered to indicate the depth towhich the centerboard projects.

To enable the centerboard to be secured at various positions, I providethe trunk a with means for engaging the centerboard. In Figs. 5, 6, and7 I show the securing means as a set-screw t engaging a threaded bushingj, affixed to one side of the trunk, the setscrew extending through oneside of the trunk and bearing against a segmental metallic wear-plate7c, aflixed to the centerboard,

'said wear-plate being 'concentric with the pivot d.

In Figs. 8 and 9 I yshow a set-screw i/ provided wlth a socket t2, adated to engage a removable wrench or han le i3, the socketed set-screwbeing engaged with a bushing j', affixed to the trunk a. i Thelast-described yconstruction enables the outer end ofthe setscrew to besubstantially flush with the outer surface of the trunk when the handleQ13 is removed.

In Fig. 1l I show a pin m adapted to be inserted removably in orificesformed for its reception in both sides of the trunk a and in either of aseries of orifices n, formed in the centerboard, the said orilices nbeing arranged in segmental series.

1. A centerboard mounted to swing approximately ninety degrees andhaving a sl ot or channel in its upper edge for the reception of aflexible operating device or controller, the bottom of said slot orchannel being curved in the direction of the length of the centerboardto cause the said controller` to be held in contact with the bottom ofthe channel at and below the water-line.

2. A centerboard mounted to swing approximately ninety degrees andhaving a curved slot or channel in its upper edge, combined with a trunkor casing to which the ccnterboard is ivoted, and a flexible controllersecured to tlie centerboard between the sides of the slot, the saidtrunk and centerboard having means for guiding the controller.

3. A centerboard provided with a controller receiving slot or channel,having sprocket-teeth at its bottom, combined with a sprocket-chainsecured between the walls of the slot, and adapted to engage the teeth.

4. rThe combination of a trunk or casing, a centerboard pivoted thereto,and means supported by the trunk at a distance from the pivot forsecuring the centerboard to the trunk in various positions to preventthe centerboard from swinging in either direction.

5. The combination of a trunk or casing, a centerboard pivoted thereto,and a securing device supported by the trunk at a distance from thepivot and adapted to engage the centerboard to hold the latter invarious positions and to prevent the centerboard from swinging in eitherdirection.

6. The combination of a trunk or casing, a centerboard pivoted thereto,and provided with a segmental wear-plate concentric with the center ofoscillation, and a set-screw engaged with the trunk and adapted to abutagainst said wear-plate.

7. A centerboard trunk or casing having an internally-threaded bushing,and a socketed set-screw engaged with said bushing and provided with adetachable handle, said setscrew being adapted to abut against accnterboard in the trunk or casing.

In testimony whereof I have allixed my signature in presence of twowitnesses.

DONALD M. MCLEAN.

Witnesses:

C. F. BROWN, E. BATGHELDER.

IOO

IIC

